Lost a photo in Lightroom

A photo I shot and edited in lightroom appears to have dissapeared into the ether.

As I scroll through, I go from DSC01590, to DSC01591 straight to DSC01593. No filters on or anything; I've searched thoroughly. 

01592 is the shot I am looking for. I know it's not a figment of my imagination - as I edited it in LR, and  exported major edits from lightroom of that photo to send to friends (at low res) - so it must've been in lightroom at some point!

It's not in 'deleted' section of lightroom either, and I'm confident that I didn't delete it and then permanently delete it. It was shot on december 16th so less than 60 days ago - so should still be there if I fat fingered and deleted.

Any idea what could have happened? Not just for this photo but if this happens once I worry it could happen again...